ArrayQuantColumn.h

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// # ArrayQuantColumn.h: Access to an Array Quantum Column in a table.
// # Copyright (C) 1997,1998,1999,2000,2001
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library is distributed in the hope that it will be useful, but WITHOUT
// # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
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// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef MEASURES_ARRAYQUANTCOLUMN_H
#define MEASURES_ARRAYQUANTCOLUMN_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/Vector.h>
#include <casacore/casa/Quanta/Quantum.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class Table;
template <class T>
class ArrayColumn;
template <class T>
class ScalarColumn;
class String;
 
// <summary>
// Provides read/write access to Array Quantum columns in Tables.
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="Bob Garwood" date="1999/12/23" tests="tTableQuantum.cc">
// </reviewed>
 
// <prerequisite>
// # Classes you should understand before using this one.
//   <li> <linkto class=TableQuantumDesc>TableQuantumDesc</linkto>
//   <li> <linkto class=Table>Table</linkto>
//   <li> <linkto class=ArrayColumn>ArrayColumn</linkto>
//   <li> <linkto class=Quantum>Quantum</linkto>
// </prerequisite>
 
// <synopsis>
// The ArrayQuantColumn class provides read/write access to quanta
// stored in a array Quantum Table column.  The Quantum column should
// already exist in the table and would have been defined by means of a
// <linkto class=TableQuantumDesc>TableQuantumDesc object</linkto>.
// In addition,
// for a ArrayQuantColumn object to be useful the column should
// contain Quanta.
//
// The ArrayQuantColumn class is the array version
// of the <linkto class=ScalarQuantColumn>ScalarQuantColumn</linkto>
// class.
//
// <h3>Quantum Units</h3></A>
// Quanta retrieved from the column will normally have the Unit that was
// specified when the Quantum column was defined.
// However, it is possible to override the default column Unit by
// supplying a Unit in the ArrayQuantColumn constructor.
// When constructed in this fashion the retrieved Quanta will by
// default be retrieved in this unit, i.e. they will by default be
// converted to this unit.
// <br>
// By giving a unit (as a Unit or Quantum object) to a get function,
// the data can be retrieved in another unit than the default.
// </synopsis>
 
// <example>
// (See <linkto class=TableQuantumDesc>TableQuantumDesc</linkto> class
// for an example of how to define a Quantum column).
// <srcblock>
//    // Create the column object with default units "deg".
//    // It gets the quantum array from row 0 and prints it to stdout.
//    ArrayQuantColumn<Double> roaqCol(qtab, "ArrQuantDouble", "deg");
//    cout << roaqCol(0) << endl;
//    // This retrieves the same array with units converted to "m/s".
//    cout << roaqCol(0, "m/s") << endl;
// </srcblock>
// </example>
 
// <motivation>
// Add support for Quanta in the Tables system.
// </motivation>
 
// <thrown>
//    <li>TableInvOper if the Table column is null.
// </thrown>
 
// <todo asof="$DATE:$">
// # A List of bugs, limitations, extensions or planned refinements.
// <li> Support for fixed unit per array element (e.g. for positions)
//      In that case #units should match first array dimension.
// <li> Functions like getColumn, getSlice.
// <li> get as <src>Quantum<Array<T>></src>.
// <li> optimize when converting when units are the same for entire array.
// </todo>
 
template <class T>
class ArrayQuantColumn {
 public:
  // The default constructor creates a null object. It is useful for creating
  // arrays of ArrayQuantColumn objects. Attempting to use a null object
  // will produce a segmentation fault so care needs to be taken to
  // initialize the objects by using the attach() member before any attempt
  // is made to use the object.  The isNull() member can be used to test
  // if a ArrayQuantColumn object is null.
  ArrayQuantColumn();
 
  // Create the ArrayQuantColumn from the supplied table and column name.
  // The default unit for data retrieved is the unit in which they were stored.
  ArrayQuantColumn(const Table& tab, const String& columnName);
 
  // Create the ArrayQuantColumn from the supplied table and column name.
  // The default unit for data retrieved is the given unit (the data is
  // converted as needed).
  // <group>
  ArrayQuantColumn(const Table& tab, const String& columnName, const Unit&);
  ArrayQuantColumn(const Table& tab, const String& columnName, const Vector<Unit>&);
  // </group>
 
  // Copy constructor (copy semantics).
  ArrayQuantColumn(const ArrayQuantColumn<T>& that);
 
  ~ArrayQuantColumn();
 
  // Make this object reference the column in "that".
  void reference(const ArrayQuantColumn<T>& that);
 
  // Attach a column to the object. Optionally supply a default unit.
  // which has the same meaning as the constructor unit argument.
  // <group name="attach">
  void attach(const Table& tab, const String& columnName);
  void attach(const Table& tab, const String& columnName, const Unit&);
  void attach(const Table& tab, const String& columnName, const Vector<Unit>&);
  // </group>
 
  // Get the quantum array in the specified row.
  // If resize is True the resulting array is resized if its shape
  // is not correct. Otherwise a "conformance exception" is thrown
  // if the array is not empty and its shape mismatches.
  // <group name="get">
  void get(rownr_t rownr, Array<Quantum<T>>& q, Bool resize = False) const;
  // Get the quantum array in the specified row. Each quantum is
  // converted to the given unit.
  void get(rownr_t rownr, Array<Quantum<T>>& q, const Unit&, Bool resize = False) const;
  // Get the quantum array in the specified row. Each quantum is
  // converted to the given units.
  void get(rownr_t rownr, Array<Quantum<T>>& q, const Vector<Unit>&, Bool resize = False) const;
  // Get the quantum array in the specified row. Each quantum is
  // converted to the unit in other.
  void get(rownr_t rownr, Array<Quantum<T>>& q, const Quantum<T>& other, Bool resize = False) const;
  // </group>
 
  // Return the quantum array stored in the specified row.
  // <group>
  Array<Quantum<T>> operator()(rownr_t rownr) const;
  // Return the quantum array stored in the specified row, converted
  // to the given unit.
  Array<Quantum<T>> operator()(rownr_t rownr, const Unit&) const;
  // Return the quantum array stored in the specified row, converted
  // to the given units.
  Array<Quantum<T>> operator()(rownr_t rownr, const Vector<Unit>&) const;
  // Return the quantum array stored in the specified row, converted
  // to the unit in other.
  Array<Quantum<T>> operator()(rownr_t rownr, const Quantum<T>& other) const;
  // </group>
 
  // Put an array of quanta into the specified row of the table.
  // If the column supports variable units, the units are stored as well.
  // Otherwise the quanta are converted to the column's units.
  void put(rownr_t rownr, const Array<Quantum<T>>& q);
 
  // Test whether the Quantum column has variable units
  Bool isUnitVariable() const { return (itsArrUnitsCol || itsScaUnitsCol); }
 
  // Returns the column's units as a vector of strings.
  // An empty vector is returned if the column has no fixed units.
  Vector<String> getUnits() const;
 
  // Test if the object is null.
  Bool isNull() const { return (itsDataCol == 0); }
 
  // Throw an exception if the object is null.
  void throwIfNull() const;
 
 protected:
  // # Quantum column's units (if units not variable)
  Vector<Unit> itsUnit;
 
  // Get access to itsUnitsCol.
  // <group>
  const ArrayColumn<String>* arrUnitsCol() const { return itsArrUnitsCol; }
  const ScalarColumn<String>* scaUnitsCol() const { return itsScaUnitsCol; }
  // </group>
 
 private:
  // # The underlying data column stores the quantum column's data.
  ArrayColumn<T>* itsDataCol;
  // # Variable units array column if applicable.
  ArrayColumn<String>* itsArrUnitsCol;
  // # Variable units scalar column if applicable.
  ScalarColumn<String>* itsScaUnitsCol;
  // # Units to retrieve the data in.
  Vector<Unit> itsUnitOut;
  // # Convert unit when getting data?
  Bool itsConvOut;
 
  // Initialize the ArrayQuantColumn from the specified table and column.
  void init(const Table& tab, const String& columnName);
 
  // Deletes allocated memory etc. Called by ~tor and any member which needs
  // to reallocate data.
  void cleanUp();
 
  // Get the data without possible conversion.
  void getData(rownr_t rownr, Array<Quantum<T>>& q, Bool resize) const;
 
  // Assignment makes no sense in a read only class.
  // Declaring this operator private makes it unusable.
  ArrayQuantColumn& operator=(const ArrayQuantColumn<T>& that);
 
  // Comparison is not defined, since its semantics are unclear.
  Bool operator==(const ArrayQuantColumn<T>& that);
};
 
}  // namespace casacore
 
// # Make old name ROArrayMeasColumn still available.
#define ROArrayQuantColumn ArrayQuantColumn
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/measures/TableMeasures/ArrayQuantColumn.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif